investigating effects of different values of chitosan polysaccharide on growth parameters in rainbow trout (oncorhynchus mykiss)

abstract 900 rainbow trout (mean weight 25 gr) were obtained from a local fish farm in urmia city and after acclimatization for 10 days, the fish were randomly divided into four groups (with three replication) and fed for 8 weeks with 0 (control), 2/5, 5 and 10 g chitosan/kg feed, respectively. finally treatments were fed the control diet (without any chitosan) for another 3 weeks. body weight, total length, food conversion rate, special growth rate, condition factor and daily weight gain were determined every two week and at the end of the trial. data were analyzed using spss ver. 20. results depicted no positive effects of chitosan on growth and nutritional parameters of rainbow trout, however, treatment four considerably (10 g chitosan/kg feed) inhibited live weight gain, total length increment and deteriorated food conversion rate (fcr) and specific growth rate (sgr) in comparison to control group and third treatment (5 g chitosan/kg feed).